Kamin

im in the final stages of my swap and am trying to figure out the last loose ends. the big one thats holding me up is the coolant line that runs from the front tube between the heads, through the TB and out to the radiator (on the camaro/bird/am). im bypassing the throttle body but am kinda lost as to what to do with the line itself.

can i just attach a small hose, bleed the air out and cap it? is it 100% necessary to have it plumbed back to the radiator or near the water pump?

thanks guys, couldnt have done this swap without you all <3

LS1MCSS

iTrader: (18)

It needs to be hooked back in to the radiator, or you can tap into the water pump as some others on here have done.

eagleuh1

I tapped into a high point on my heater return line. Works good so far. Just make a tee or buy one.

Kamin

hmm heater line it is! lol

TXjeepTJ

iTrader: (8)

i read in the 'ls1 performance' book that if you cap it off you'll add a little horsepower(like .2hp im guessing)

Kamin

where is this book and who wrote it lol

67rsss

iTrader: (4)

I am having a hard time understanding how allowing steam pockets to build in the head will improve performance. I don't think .2HP is worth blowing a head gasket or worse.... Just pull a little weight of the car if that little bit of HP makes a difference for you.

owen v8litew8

I used a coupler for my lower rad house and tapped it into that metal coupler but man the heater hose idea is a good one.

some people have capped it and had no problems but its pretty simple to run it to the rad hoses, the radiator or the heater core hoses, so might as well run it.

Nemesis68

iTrader: (2)

I think that its more like .000002HP.

NemeSS

iTrader: (127)

run to heater hose, or rad. or catch can,
dont cap off.

Kamin

if anyone does it for the hp gain they are idiots. for me its to make the cooling system on my engine as simple as possible. not going to have lines running everywhere unless i have to.

im going to tap into the heater hoses.

Indyjc

iTrader: (1)

I'm using a stock radiator so I'm using the steam hose just like the factory. There are guys on here that have plugged it and have not had any problems. I have talked to a guy with a gto who plugged his 2yrs. ago and no problems. But if the factory designed it that way they must know something.

Kamin

the factory has alot of bullshit they have to deal with (emissions) so dont think they do everything for utmost reliability and performance.

TXjeepTJ

iTrader: (8)

its a pretty popular book lol

G-Body

iTrader: (4)

1. I have never read the book, or for that matter even seen the book in person, however when they say cap the TB bypass I believe that they mean re-routing the steam line so that it comes off the head and goes directly to the radiator and then putting caps on the TB because there are no longer any hoses to connect to it. I do not believe that they mean to remove the steam line to the radiator completely, just to re-route it so that there is no longer hot coolant flowing through the TB. From what I have read online you usually do pick up ~2hp at the wheels because the 200+ degree coolant is not heating up the TB/incoming air.

2. So far I have seen 4 locations to connect the line to, the radiator, the heater hose, tap the water pump and the upper radiator hose. The radiator is the best place to put it because any air will rise to the radiator cap and be purged into the overflow tank. Second best would be the upper rad hose, because the air will be pushed into the rad and hopefully be purged. The heater hose and water pump are OK locations but I would avoid them if possible. The water pump is a pain because you have to drill and tap it, plus if you ever kill a pump in the middle of no where you will have to drill the new pump. The heater hose is ok and that is where I have my steam line routed to, heck GM even routes the line there on some of the SUV`s they produced, but I would avoid it because I feel it has the tendency to air lock the heater core. The water pump on the LSx motors does not have a lot of flow through the heater core, and I have had my heater core become air bound at least twice, I think it has something to do with steam coming out if the line and filling the heater core with air.

3. Do NOT connect it to the overflow tank/catchcan unless that is where your radiator cap is, most of the older cars have a catch can that is at atmospheric pressure (vented) and the radiator side of the cooling system is pressurized. If you connect it to the catch can on a car like that the coolant will be forced out of the engine/radiator and into the catch can until the engine/radiator is empty and the catch can is overflowing.

4. From what I have read GM ran the steam line through the TB in order to heat the TB to prevent icing in extremely cold weather but mostly to aid in cold start warm-up. (less cold-start emissions and faster warm-up times)

eagleuh1

Yeh, they are just talking bypassing the throttle body with the steam vent going straight to the radiator or hose tee. you shouldn't be getting air out this line once you've filled and vented and filled and vented. It's a steam vent. The steam should cool and condence once it hits the less hot coolant in the heater hose.

NismoSilvia270R

iTrader: (1)

keep it higher than the nipple ie. rad , upper rad hose .... the heater hoses may not be high enough to do any good.

reason for the air to be able to come out with out a hitch.

you arent using an sr20 radiator with the upper hose on the driverside, but if you were, ted j's car did something neat using a 3in metal tube and a nipple off it.

heres the post: https://ls1tech.com/forums/showpost....&postcount=140

NoHope

So the coolant bypass line offers absolutely no HP increase or added throttle response, and it's not good for cars in really cold environments?

69 Ghost

If you have ever experienced an iced up carb you will know why they put this in. Personally I would not remove it unless you are in a warm climate and really think it is going to do any good.

bczee

iTrader: (12)

+1 on G-Body's words..

I alway by pass my TB .. I don't even cap it.. I run mine to the Radiator, as I have ports on both of my swaps..

I would not think you would need to route it through the TB unless you drive in cold climate and should be used for good driveablity if you have issue due to the cold.

BC